Method of strip cutting raw potatoes

ABSTRACT

Raw potatoes are heated throughout to a temperature of 130-145° F and then are hydraulically passed through a knife device provided with strip cutter members.

RELATED APPLICATION

The present application is a division of my allowed copendingapplication Ser. No. 745,537, filed Nov. 29, 1976, now U.S. Pat. No.4,082,024.

BACKGROUND OF THE INVENTION

1. Field

The invention is in the field of methods and apparatus for slicingagricultural produce of the nature of potatoes.

2. State of the Art

The system shown and described in U.S. Pat. No. 3,109,468, issued to F.G. Lamb et al. on Nov. 5, 1963, for "Vegetable Slicing Apparatus", isindicative of the state of the art which it was the major objective ofthis invention to improve. No indication is given there that thepotatoes should be preconditioned. Although it had been recognized thatbeets should be treated by blanching within vaguely indicated limitsprior to slicing in a centrifugal slicing machine, no indication hadbeen given that a somewhat similar but carefully controlled pretreatmentof potatoes for hydraulic-stream, strip-cutting thereof to produceFrench fry and similar elongate cuts would enable speed-up ofproduction, without undesirable fractures in and ragged appearance ofthe cut potato product. U.S. Pat. No. 2,597,066 to H. M. Chase, asissued May 20, 1952, for "Process for Preparing and Preserving FrozenPotatoes" teaches initial blanching (customarily 160° F. minimum)followed by peeling and then dousing with ice water prior to passing theso-conditioned potatoes through strip cutters or slicing machines, butpatents issued to F. G. Lamb et al. for improvements subsequent to theone previously mentioned have given no indication that advantages couldbe had by preconditioning of the potatoes.

SUMMARY OF THE INVENTION

Conditioning of the potatoes prior to cutting is carried out inaccordance with this invention by maintaining the potatoes in a heatedenvironment having a temperature within the range of substantially 130°to 145° F. for a period of from about forty to sixty minutes in order toheat them throughout. A longer time is not normally detrimental but isnot economical. We have found that this preconditioning alters thecharacteristics of the potatoes such that hydraulic-stream,strip-cutting thereof produces a superior cut product more rapidly thanheretofore. This is true whether or not the potatoes are subjected topeeling procedures before or after the conditioning.

The conditioned potatoes are properly aligned end-to-end in thehydraulic stream by passing them through improved aligning mechanism,which positions them most advantageously for movement at high speed intothe improved knife device of the invention. It is not necessary to sizethe potatoes first, nor is the invention restricted to any particulartype of potato. The improved knife device has a blade arrangement ofpyramidal formation diverging away from the approaching potatoes so thatthe apex thereof faces the oncoming potatoes and is substantiallycentered in the hydraulic stream. The system of the invention,considered as a system, does not distinguish nor separate center cutsfrom side cuts, as does the Lamb et al. system in producing center cutsand side slabs and separating the one type of cuts from the other, but,on the contrary, cuts the entire potato into strips indiscriminantly.

The aligning mechanism of the invention is positioned in an elongatesection of the hydraulic conduit, which is preferably square in rightcross-section and positioned immediately in advance, i.e. upstream, ofthe cutter device. It comprises sets of mutually opposite, elongatewalls mounted for simultaneous and equal movement toward and away fromthe longitudinal axis of the conduit section, the movement beingtraversely of but along the lengths of the walls from their upstreamends which are pivotally fixed in position, to their downstream endswhich are freely movable. As these walls are moved inwardly toward butshort of the center of the conduit, they progressively and symmetricallydecrease the effective cross-sectional area of the conduit until thewalls of the two sets meet to limit such decrease to a predeterminedminimum. Outward movement away from the center of the conduit is limitedby the fixed outer walls of the conduit section.

Means are provided for normally maintaining these walls of the aligningmechanism in the position of minimum cross-sectional area as againstoutward pressure of the hydraulic stream flowing therethrough, but foreffecting simultaneous and equivalent outward movement of such wallsunder lateral pressure of relatively large potatoes or of those askew inthe stream, regardless of which wall or walls such potatoes impingeagainst.

It has been found that the aligning of potatoes afforded by thisimproved mechanism is especially advantageous when utilized inconjunction with the improved knife device of the invention, but use ofsuch mechanism is not so limited. It may be used for whatever advantagesmay accrue in conjunction with other knife devices, for example those ofthe aforementioned Lamb et al. patents.

Besides the pyramidal configuration of the blades of the improved knifedevice of the invention, the nested arrangement thereof provideseffective support for the individual blades and is highly significantpart of the invention, in that it enables thinner blades to be used andthereby increases the rapidity of cutting action. Moreover, the bladesremain sharper longer. Again, this improved cutter device may be usedwhenever found advantageous, for example, with the aligning andcentering mechanisms of the aforesaid Lamb et al. patents.

THE DRAWINGS

In the accompanying drawings, which illustrate both method and apparatuspresently contemplated as the best mode of carrying out the invention inactual practice:

FIG. 1 is a flow sheet in the nature of a block diagram showing theseveral essential steps of the method;

FIG. 2, a view in front elevation of the improved potato strip cutter;

FIG. 3, a view in side elevation;

FIG. 4, a fragmentary vertical section taken on the line 4--4 of FIG. 2and drawn to a larger scale, the aligning mechanism being in thenormally maintained, minimum cross-sectional area condition;

FIG. 5, a horizontal section taken on the line 5--5 of FIG. 2 and drawnto the larger scale of FIG. 4, portions being broken out for convenienceof illustration;

FIG. 6, a view corresponding to that of FIG. 5 but showing the mechanismin its maximum cross-sectional area condition;

FIG. 7, a view corresponding to that of FIG. 6 but drawn to a smallerscale and showing the complete mechanism;

FIG. 8, a bottom plane view of the knife device per se considerablyenlarged;

FIG. 9, a fragmentary vertical section taken on the line 9--9 of FIG. 8and drawn to a still larger scale;

FIG. 10, a vertical section taken on the line 10--10 of FIG. 8; and

FIG. 11, a similar view taken on the line 11--11 of FIG. 8.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENT

In accordance with the method, raw potatoes to be cut into strips arepreconditioned by controlled heating throughout their bodies in suitableequipment, such as a holding tank through which heated water iscontinually circulated. The potatoes are held in the tank for a periodof from thirty to sixty minutes, depending upon the temperature of thewater, which is maintainted at from about 130° to 145° F. The potatoesshould have attained a body temperature throughout that is substantiallyno less than 130° F. but short of the temperature that will gelatinizestarch, i.e. about 145° F., in order to avoid ragged and fractured cutson the one hand and undue toughness and resistance to slicing on theother. The potatoes processed may be of any type, and there is no needto size them.

The conditioning treatment may be and preferably is in advance of theusual scrubbing, peeling, and trimming operations, the conditioned andpeeled potatoes being carried through the several subsequent operationssequentially, preferably from a suitable pump-feed tank from which theypass into a high velocity food pump, indicated 12 in FIGS. 2 and 3. Theyare discharged by the pump, as part of a high velocity stream of water,into a usual type of accelerator-singulator, shown in FIGS. 2 and 3 as avertically positioned, convergent conduit 13 leading into the alignmentmechanism 14 of the invention. Mechanism 14 is positioned immediately inadvance, i.e., upstream, of the knife device 15 of the invention, intoand through which the potatoes are hydraulically carried withconsiderable force and speed usual to a system of the type concerned.The cut product is discharged into and carried through a conduit 16 bywhich it is preferably carried to a dewatering stage forming no part ofthe present invention.

ALIGNMENT MECHANISM

In its illustrated form, the improved aligning mechanism 14 of theinvention comprises an elongate conduit section 17, see particularlyFIGS. 4, 5, and 6, uniformly square in right cross-section and havingfixed and rigid outer walls 17a providing a flow passage for thehydraulically carried, singulated stream of conditioned potatoes leadingdirectly into the improved knife device 15 of the invention. Internallyof this conduit section 17 are movable elongate walls that include a setof mutually opposite walls 18 extending along the length of the conduitsection and entirely across one transverse dimension thereof, and asecond set of mutually opposite walls 19 extending along the length ofthe conduit section between the walls 18 of the first set but convergingalong their lengths from their ends that are remote from knife device 15to their opposite ends that are relatively adjacent to such knifedevice.

Movable walls 18 and 19 are pivotally fastened, FIG. 4, at their saidremote ends to conduit 17 at the inner faces of corresponding walls 17athereof by any suitable means. As shown, these ends are outwardlyflanged and mounted in corresponding recesses in the lower flanged end17b of conduit 17, enough leeway being provided for the very limitedrocking action required during movements of walls 18 and 19.

Alignment mechanism 14 and knife device 15 are interposed betweenconduits 13 and 16. Both are removably associated with each other andwith their respective conduits, so the blades may be removed forsharpening or for replacement and so that any debris that might collectbehind the walls 18 and 19 of the alignment mechanism can be removedfrom time to time.

It will be noted that walls 18 and 19 are provided with slots 20 inorder to minimuze the hydraulic pressure differential at opposite sidesof such walls.

Alignment mechanism 14 comprises means for normally maintaining walls 18and 19 in the closed position, i.e. the condition of minimumcross-sectional area of the flow passage 21 therethrough, as indicatedin FIGS. 4 and 5, against outward hydraulic pressure on such walls, yetanabling such walls to move outwardly, simultaneously and equally, underimpact of potatoes on one or more of such walls. As illustrated, suchmeans preferably take the form of pins 22 mounted in respective sleeveslideways 23 and operable against individual walls 18 and 19,respectively, of the two sets of such walls. Each of the pins 22 isprovided with a dependent cam wheel 24, operable against respective camtracks 25 which are mounted on a rotatable plate 26 that is resilientlybiased by coil springs 27 anchored at one end to a reaction ring 28 andat the other end to respective arms 29 which extend outwardly from thecorners of plate 26. Reaction ring 28 is adjustably mounted onsupporting crossarms 30 affixed by means of a square collar 30a toconduit section 17. Plate 26 is rotatably mounted on conduit section 17as by means of a ring 26a rotatably carried by a circular bearing plate26b affixed to conduit 17.

As potatoes are hydraulically carried in single file at a considerablespeed through passage 21 toward knife device 15, they either pass intosuch knife device without impinging against one or more of the walls 18and 19 of alignment mechamism 14, or, due either to excessive size orlongitudinal misalignment, they forcibly impinge against one or more ofsuch walls 18 and 19.

If any one or more of the potatoes through alignment mechanism 14impinges against one or more of the walls 18 and 19, the wall or wallsconcerned are forced outwardly away from the longitudinal axis ofpassage 21 against the opposite of a corresponding pin or pins 22.Regardless of how few walls are involved in the impingment, all of thewalls 18 and 19 will be moved simultaneously and equally by reason ofthe four sets of cam wheels 24 and cam tracks 25 associated with therespective pins. Likewise, such walls will be simultaneously and equallyreturned to their normal positions of FIGS. 4 and 5 by action of thesprings 27 when there is no longer potato impingement.

It should be noted that the lower ends of walls 18 and 19 are retainedin position by means of a collar 32, FIG. 4, welded or otherwise securedto the adjoining end of conduit 13, and that the pump and severalconduits are maintained in position by suitable supporting structureindicated fragmentarily at 33, FIGS. 2 and 3.

KNIFE DEVICE

Knife device 15 is removably mounted in a holder 34, FIG. 4, welded orotherwise rigidly affixed to the upper end of conduit 17 and having aflange 34a removably secured, as by bolting, to a corresponding flange16a of discharge conduit 16. It comprises a series of knife blades 35,see especially FIGS. 8-11, and a series of transversely-extending knifeblades 36, both removably mounted in a frame 37 and interengaged in anested, open mesh arrangement of pyramidal formation. The apex of sucharrangement confronts the oncoming stream of hydraulically carriedpotaotes, i.e. is directed toward alignment mechamism 14.

In the form illustrated the apex, 15a, is provided by a protrudingcentral blade 38, the series of blades 35 being interrupted centrallythereof by such apex blade 38. Likewise, the series of blades 36 isinterrupted by a blade 39, but at a level in the knife device inset withrespect to protruding blade 38. All of the blades 36 are similarly insetin the knife device with respect to their respective adjoining blades35, so that the initial incisions start potato slices, followed shortlythereafter by transverse cuttings of the incipient slices into potatostrips.

A feature of the invention is the arrangement of cutting-edge-forminglevels on the respective knife blades of each series, so there will beno binding of the cut potato strips as they pass through the respective,mutually adjoining, box cutters, 40, FIG. 8, making up the knife device.Thus, each of the individual box cutters 40 are fronted by a pair ofslicer knife edges 41, disposed at mutually different levels, which arebacked transversely thereof by a pair of stripper knife edges 42, alsodisposed at mutually, different levels, to form an entryway into the boxpassageway 40a extending through such individual cutter. Each pair ofslicer knife edges 41 and each pair of stripper knife edges 42 comprisesa beveled edge margin 41a and 42a, respectively, and an unbeveled edgemargin 41b and 42b, respectively, the former being substantiallyentirely in advance of the latter, as illustrated.

It will be noted that apex blades 38 and 39 are beveled at both sides ofknife edges 41 and 42, respectively, in providing beveled edge marginsfor adjoining box cutters at opposite sides thereof.

As so constructed, the blades of the knife device spread initially-cutportions of a potato before respective successive cuts are made, therebysmoothly accomodating advance cut portions of the partially cut potatoin the knife device without binding as the potato passes through theside-by-side adjoining, individual box cutters 40 making up the knifedevice.

The several blades making up knife device 15 are of chevron formationand are preferably mounted in respective slots provided in the interiorface portions of the frame members of frame 37, there being slots 43,FIG. 8, in the respective, mutually opposite, frame members 37a, andslots 44 in the respective, mutually opposite, frame members 37b. Theblades are nested by the provision of slots in the backs of those of oneset for receiving the fronts, i.e. cutting edge portions, of those ofthe other set. In the illustrated embodiment, there are slots in thebacks of the blades 35 and of apex blade 38 for receiving the cuttingedge portions of the blades 36 and of central blade 39.

For convenience of insertion and removal of the individual blades tosharpen them from time to time and to make replacements if and when oneor more are seriously damaged for one reason or another, as, forexample, by a foreign object being inadvertantly present in the streamof potatoes projected against the cutting edges, slots 43 and 44 arepreferably open at opposite ends thereof but receive the blades in aclose frictional fit so such blades are normally held tightly in place.To prevent backward ejection of the blades during cutting, a plate 45,FIG. 4, peripheral to flow passage 21, is interposed between flange 34aof knife holder 34 and flange 16a of discharge conduit 16. Such plate 45overlaps the slotted frame members of knife frame 37 and closes thecorresponding ends of the slots. To prevent forward ejection of theblades under extraordinary circumstances, triangular recesses areprovided forwardly in the slotted interior face portions of framemembers 37b for the reception of correspondingly triangular,blade-keeper blocks 46, which are held in place by respective screws 47,FIGS. 10 and 11.

By reason of the nested arrangement of the knife blades, they areself-supporting throughout and can be made thinner than otherwise, e.g.of steel 25/1000 of an inch in thickness. During operation, they nesttogether tighter and tighter by reason of the cutting pressure, and, aspreviously mentioned, they spread the incised potato portions during thecutting operation to prevent binding of the cut portions as they passthrough the invididual box cutters. Because the potato sections are notcompressed as they pass through the knife device, the cutting operationis faster and the blades last longer. It has been found that the singlebevel cutting edges on the majority of the blades are advantageous, inthat they retain their edges longer and provide superior cuttingperformances.

OPERATION

In the strip cutting of potatoes, the raw potatoes are conditioned forcutting and peeled as previously described and carried hydraulically insingle file into and through the alignment mechanism, whereby thosewhich are of elongate configuration are individually aligned with theirrespective longitudinal axes extending substantially along thelongitudinal axis of the hydraulic stream. The individual potatoes arethen projected with great force, by reason of the velocity of the streamof water by which they are carried, toward, into, and through the knifedevice, being cut into strips by the multiplicity of box cutters makingup such knife device. In contrast to previous systems of the typeconcerned, the entire potato is cut into strips. No slab cuts are madeat the outside of the potato. This has been found to be unnecessary andundesirable from the standpoint of economy of operation and of product.

It should be realized that other types of vegatables can be strip cut bythe apparatus of the invention and that dimensions of the various partsmay be adjusted to suit any given instance of use.

Whereas this invention is here illustrated and described with specificreference to an embodiment thereof presently contemplated as the bestmode of carrying out such invention in actual practice, it is to beunderstood that various changes may be made in adapting the invention todifferent embodiments without departing from the broader inventiveconcepts disclosed herein and comprehended by the claims that follow.

We claim:
 1. In the strip cutting of raw potatoes by hydraulicallypassing said raw potatoes through a knife device provided with stripcutter members, the improvement comprising first subjecting the potatoesto a conditioning treatment at a temperature within the range ofsubstantially 130° to 145° F. for a period of time sufficient to heatthe potatoes entirely throughout to a corresponding temperature.
 2. Amethod in accordance with claim 1 wherein the potatoes are peeledsubsequent to conditioning but before being strip cut.
 3. A method ofstrip cutting raw potatoes, comprising subjecting the potatoes to aconditioning treatment at a temperature within the range ofsubstantially 130° to 145° F. for a period of time sufficient to heatthe potatoes entirely throughout to a corresponding temperature; andhydraulically passing the conditioned potatoes through a knife deviceprovided with strip cutter members to strip cut said conditionedpotatoes.
 4. A method in accordance with claim 3, wherein the potatoesare peeled subsequent to conditioning but before being passed throughthe knife device.